Hiding kerf cuts for deck rimjoist

[Nickhxc4life]

Not sure if this belongs here but here it goes. I plan to build a floating deck this summer. There is a portion of it which will be rounded. In order to make it rounded, I will need to kerf cut the rim joist for the rounded section. How do I hide the kerf cuts in the rim joist without overlapping it with the deck boards?

[Nickhxc4life]

I may have misspoke....the rounded side of the deck won’t have rim joists it will have a fascia board more or less but you get the idea. If I butt the deck boards against it the kerf cuts will be exposed. 

[Tpt life]

Rim joist is a term that talks about a structural support underneath the deck surface. It seems you are attempting some form of banding. I don’t know a good way to band a deck like that. Hopefully someone else can help. That’s not a thing I have seen done. 

[wtnhighlander]

How large is the curve's radius? If it is fairly tight, you might get away with routing a recess on the visible edge and cutting a curved strip from a wide board to fill it, hiding the kerfs. But something like that is not going to stay together well outdoors.

Another option for a smallish radius would be to carve out a curved corner piece from a thicker block, then but the straight facia boards against it.

If you are doing a long, sweeping curve, carving curved facia from thicker stock might be possible, but likely to leave you with several butt joints along the span.

[Wimayo]

I think the best way to do this is to laminate your curved piece. Of course, you will need to use an exterior glue.

[Nickhxc4life]

Thanks for the replies guys. I know it can be done as it’s been talked about a lot I just can’t wrao my head around how to hid the kerf. I haven’t modeled it yet but it will be a long sweeping curve. Wider stock cut curved will not get the job done. 

[drzaius]

What kind of wood? It is surprising how tight a radius you can get by steaming bending. Check out this video . He bends 2.25" thick red oak to a 30" radius. If it's a wide sweeping curve, then I bet you could do it even with kiln dried stock.

Edit: Another thought. If you aren't opposed to composite decking (I am), It bends very easily when it's heated. There are several videos showing the process.

[G Ragatz]

I wonder if filling the kerfs with a glue/sawdust mixture might work?  Put it in the cuts before you bend, and scrape/sand after.  It certainly wouldn't be invisible with a clear finish, but better than nothing.

How are you planning to finish the deck surface?

[wtnhighlander]

A lot depends on the deck material, too. Most of the proposed solutions aren't going to do well with home center treated pine decking. 

For a long sweep, steam bending could work, as could bent laminations, with the right glue. How will you fasten the facia in place, and how will the deck be finished?

[Minnesota Steve]

If you cut out the backs to bend the wood, will this make it more likely to rot out?

 

[drzaius]

37 minutes ago, Minnesota Steve said:

If you cut out the backs to bend the wood, will this make it more likely to rot out?

That's a good point. Dousing those kerfs with preservative would be in order. I can't see any way of hiding the kerfs unless the decking is run over top of the banding. I still think steam bending would deliver the best, strongest & most appealing result.

[woodbutcher74]

Wouldn't PVC boards bend easier without kerfing it. I believe its available with wood grain embossed into it? Just a thought.

[pkinneb]

11 hours ago, woodbutcher74 said:

Wouldn't PVC boards bend easier without kerfing it. I believe its available with wood grain embossed into it? Just a thought.

Yes. You are also correct about the wood grain although its raised grain. I used it our deck.